===============
=============== ↑↓
=============== ↑↓
=============== ↑↓
=============== ↑↓
=============== ↑↓
=============== ↑↓
=============== ↑↓
===============
(次項参照)
===============
=============== ↑↓
=============== ↑↓
=============== ↑↓
=============== ↑↓
=============== ↑↓
=============== ↑↓
=============== ↑↓
===============
(次項参照)